EP2351104A2 - Module photovoltaïque concentrateur - Google Patents

Module photovoltaïque concentrateur

Info

Publication number
EP2351104A2
EP2351104A2 EP09765166A EP09765166A EP2351104A2 EP 2351104 A2 EP2351104 A2 EP 2351104A2 EP 09765166 A EP09765166 A EP 09765166A EP 09765166 A EP09765166 A EP 09765166A EP 2351104 A2 EP2351104 A2 EP 2351104A2
Authority
EP
European Patent Office
Prior art keywords
acrylate
assembly according
encapsulant
formulation
cured
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09765166A
Other languages
German (de)
English (en)
Inventor
Izhar Halahmi
Pasha Solel
Itay Baruchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PYTHAGORAS SOLAR Inc
Original Assignee
PYTHAGORAS SOLAR Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by PYTHAGORAS SOLAR Inc filed Critical PYTHAGORAS SOLAR Inc
Publication of EP2351104A2 publication Critical patent/EP2351104A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
    • H01L31/0543—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means comprising light concentrating means of the refractive type, e.g. lenses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042—PV modules or arrays of single PV cells
    • H01L31/048—Encapsulation of modules
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/52—PV systems with concentrators

Definitions

  • This invention relates to a light curable encapsulant for use in the construction of photovoltaic cells and modules.
  • Solar radiation is utilized by various methods to produce useable energy.
  • One method involves the use of photovoltaic (PV) cells, which convert solar radiation to electricity.
  • PV photovoltaic
  • the cost per unit power for producing electricity using photovoltaic cells can be decreased by concentrating the sunlight so that the same amount of sunlight can impinge a smaller, and thus cheaper, photovoltaic cell, from which a similar or equal amount of electricity may be extracted.
  • the price of a PV panel is primarily dominated by the cost of each of the materials used and the cost of its assembly.
  • the cost of the PV cells is significantly reduced (by 75-90%), but the cost of other materials increases and becomes an important factor.
  • the assembly of low concentration PV panel is also more complex therefore more expensive.
  • Typical PV panels that are already in the market utilize polymeric mass that encapsulates the cell and conductors and at the same time adheres to the cell and to a protective layer, to seal and protect the PV.
  • the encapsulants dominating the market are thermoplastics that are laminated under pressure and heat, usually between the PV cell and one or more protective layers, usually glass.
  • thermoplastic encapsulants such as ethylene vinyl acetate (EVA), polyvinyl butyral (PVB) and ionomer resins are the need for high pressures and temperatures during lamination, their tendency to leave voids, tendency to yellow during exposure to UV light and heat, the need for long curing periods (negative economical aspect), high modulus of elasticity that may break thin PV cells, and their poor adhesion to materials other than the materials of the PV cell and glass.
  • EVA ethylene vinyl acetate
  • PVB polyvinyl butyral
  • ionomer resins are the need for high pressures and temperatures during lamination, their tendency to leave voids, tendency to yellow during exposure to UV light and heat, the need for long curing periods (negative economical aspect), high modulus of elasticity that may break thin PV cells, and their poor adhesion to materials other than the materials of the PV cell and glass.
  • addition curing silicones have been used as encapsulants.
  • the market share of that kind of encapsulants is relatively low, due to their high price and tendency to be inhibited.
  • the advantages of silicones are high stability against yellowing and discoloration, low modulus of elasticity, and wide service temperature latitude.
  • the disadvantages are poor adhesion to plastic materials, low strength, and high risk of inhibition during curing and long curing time.
  • a concentrating object usually made of a transparent amorphous plastic material, such as poly methyl methacrylate (PMMA), cyclic olefin (COC) or polycarbonate (PC) is provided on top of the PV cell in order to increase the light intensity, to form a concentrating PV (CPV).
  • PMMA poly methyl methacrylate
  • COC cyclic olefin
  • PC polycarbonate
  • the thermoplastic encapsulants are not applicable since their lamination process is at temperatures higher than the softening temperature of the transparent plastic materials and their adhesion to the plastics is poor.
  • the alternative of utilizing addition curing silicones is also not very promising as such silicones have poor adhesion to the plastics, especially to PMMA that is commonly used as a CPV optical element.
  • the inventors of the invention disclosed herein have now developed a reliable, cost effective, encapsulated concentrating PV (CPV) that has excellent dimensional stability and discoloration resistance, obviating the use of thermoplastic encapsulants and silicone encapsulants.
  • the inventors further provide an encapsulant formulation that is a liquid at room temperature, cures readily when exposed to light and/or heat, has a high degree of transparency, high resistance to yellowing and cracking when exposed to sunlight, enough softness (low shore hardness and low modulus of elasticity) and flexibility to withstand the thermal mismatch between the transparent (amorphous) plastic materials and the glass/PV silicon during thermal cycling, has low haze and excellent adhesion to transparent (amorphous) plastic materials, such as poly methyl methacrylate (PMMA), cyclic olefin (COC) and polycarbonate (PC) to glass and/or to the silicon PV cell.
  • PMMA poly methyl methacrylate
  • COC cyclic olefin
  • PC poly
  • a photo curable or thermo curable liquid encapsulant formulation for bonding to a transparent (amorphous) plastic surface, (e.g., for encapsulating a photovoltaic cell and for bonding same to at least one plastic surface material such as plastic optics), comprising at least one high durability polymer (HDP), at least one unsaturated monomer and/or oligomer, and at least one photoinitiator.
  • said at least one HDP is at least one acrylic or methacrylic polymer (namely, a polymer or oligomer having at least 50% of its chain, repeating units derived from acrylic and/or methacrylic acid, ester, urethane or amide thereof).
  • the liquid encapsulant formulation comprises at least one acrylic polymer, at least one unsaturated monomer and/or oligomer and at least one photoinitiator and optionally at least one free radical source (to permit, upon exposure to light and/or heat, cross-linking and chain growth of the unsaturated monomers and oligomers, to thereby provide a soft and elastic mass).
  • said at least one HDP polymer is selected from aliphatic polyester, aliphatic polyurethane, and a poly vinyl butyral.
  • the liquid encapsulant of the invention wets the surfaces to be bonded substantially without the need to apply pressure and to heat the surface.
  • the encapsulant formulation of the invention has a viscosity of between about 50 and 1,000 cps at 25°C at a shear rate of 10 sec "1 .
  • the encapsulant has a viscosity of between about 150 and 5,000 cps at 25°C at a shear rate of 10 sec "1 .
  • the encapsulant has a viscosity of between about 250 and 10,000 cps at 25°C at a shear rate of 10 sec "1 .
  • a higher viscosity correlates to a higher strength, fatigue resistance, toughness and stress cracking, faster curing and lower tendency to oxygen inhibition.
  • a higher viscosity may also result in the trapping of air between the substrate and the adhesive layer and slowing down of its flow.
  • a lower viscosity lower molecular weight monomers and oligomers content in the formula is increased is, on the other hand, correlated to higher brittleness, risk of stress cracking of the bonded (amorphous) transparent polymeric surface, slower curing speed, higher tendency to inhibition by oxygen and higher risk of irritations to operators.
  • the at least one HDP is a homopolymer, copolymer or a terpolymer (random, alternate, graft or block) of acrylic or methacrylic acid esters, amides, urethanes or ethers.
  • Non-limiting examples of such acrylic or methacrylic acid esters, amides or ethers are butyl acrylate, ethyl acrylate, octyl acrylate, decyl acrylate, iso-decyl acrylate, tridecyl acrylate, ethyl hexyl acrylate, ethoxylated ethyl hexyl acrylate, octyl decyl acrylate, di- ethylene glycol 2-ethylhexyl ether acrylate, tetra decyl acrylate, cetyl acrylate, stearyl acrylate, behenyl acrylate, polyethylene glycol mono acrylate, urethane acrylate, and caprolactone acrylate.
  • copolymer and “terpolymer” as known in the art, independently of each other, refer to one or more types of monomers copolymerized by any means and selected in non limiting manner from random, block, alternate and graft copolymers and terpolymers.
  • the at least one acrylic polymer utilized in the formulation of the invention provides the liquid encapsulant controlled reaction rate during exposure to light or heat, controlled viscosity, so that the flow of the liquid encapsulant over the glass/PV silicon is controlled, and provides the cured (after exposure to light and/or heat) encapsulant with the ability to bond the PV cell to an (amorphous) transparent plastic surface such as PMMA, COC and PC, with resilience, elasticity at low temperatures (below zero degrees), strength, high transparency, low level or even zero stress-cracking to plastic surfaces such as PMMA, COC and PC and low haze. Since the cured mass which is obtained is exposed to sun light and high temperatures during service, it is another object of the present invention to use HDP, monomers and oligomers that are resistant to UV light induced degradation and to thermal induced degradation.
  • the concentration of the at least one HDP in the formulation is at least 10% of the total weight of the formulation. In other embodiments, the concentration is between 10 and 90% of the total weight of the formulation. In other embodiments, the concentration is between is 15 and 75% of the total weight of the formulation. In still further embodiments, the concentration is between 20 and 65% of the total weight of the formulation.
  • the unsaturated monomer or oligomer is selected so as to be stable against degradation induced by UV radiation (UV light) or heat (as polymerized/ cross-linked matter), namely not to undergo degradation under such conditions, be it short term or long term.
  • Each of said at least one unsaturated monomer or oligomer has at least one reactive group per molecule, said reactive group being selected from acryl, vinyl, allyl and unsaturated polyester.
  • Typical oligomers and monomers that provide light and heat stable polymers are of the aliphatic, cycloaliphatic and/or the heterocyclic type. Polymers having aromatic groups (as part of the main backbone or as pendant or end- groups) should be avoided.
  • the monomers are selected amongst mono, di, tri or polyfunctional moluecleus having a molecular weight of between about 30 and 30,000 daltons.
  • An oligomer would typically comprise two or more such monomers.
  • Non-limiting examples of said at least one unsaturated monomer are long chain alkyl acrylate or methacrylate esters such as lauryl methacrylate, butyl acrylate, octyl acrylate, decyl acrylate, iso-decyl acrylate, tridecyl acrylate, ethyl hexyl acrylate, ethoxylated ethyl hexyl acrylate, octyl decyl acrylate, di-ethylene glycol 2-ethylhexyl ether acrylate, tetra decyl acrylate, cetyl acrylate, stearyl acrylate, behenyl acrylate, polyethylene glycol mono acrylate and caprolactone acrylate 2-ethyl hexyl acrylate, polyethylene glycol acrylate, urethane acrylate, polyester acrylate and any methacrylate equivalent thereof.
  • Non-limiting examples of said at least one unsaturated oligomer are urethane acrylate and polyester acrylate.
  • the encapsulant formulation comprises between about 5 and 75%, 85% or 95% of at least one acrylate monomer.
  • the encapsulant formulation comprises between about 5 and 75% of at least one alkyl acrylate monomer.
  • the encapsulant formulation comprises between about 5 and 75% of at least one urethane acrylate monomer.
  • the encapsulant formulation comprises between about 5 and 75% of at least one polyester acrylate monomer.
  • the liquid encapsulant formulation comprises at least one photoinitiator, as well as at least one acrylic, methacrylic polyurethane and/or polyester polymer, monomer or oligomer, so the curing of said encapsulant is achieved within a few seconds to a few minutes upon exposure to UV light and/or visible light.
  • Non-limiting examples of said at least one photoinitiator are 2-hydroxy-2- methyl- 1 -phenyl-propan- 1 -one, 2,4,6-trimethylbenzoyl-diphenyl-phosphineoxide, 1 - hydroxy-cyclohexyl-phenyl-ketone, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentyl phosphine oxide, 1 - [4-(2-hydroxyethoxy)-phenyl] -2-hydroxy-2-methyl- 1 -propane- 1 - one, 2,2-dimethoxy-l,2-diphenylethan-l-one and 2-methyl-l[4-(methylthio)phenyl]-2- mo ⁇ holinopropan- 1 -one .
  • said at least one photoinitiator is reactive in the UV and visible spectrum. In some other embodiments, said at least one photoinitiator being activated by light in the visible spectrum, allows curing to be achieved when light is provided through glass or other UV screening protective layers.
  • photoinitiators are phenyl phosphine oxides such as Irgacure 819 manufactured by Ciba, and Lucirin TPO manufactured by BASF.
  • the concentration of said at least one photoinitiator is between 0.05% and 10% of the total weight of the liquid formulation.
  • the encapsulant formulation may further comprise at least one adhesion promoting agent selected from (1) monomers, oligomers or polymers having at least one acidic side or end groups, such as acrylic acid, a phosphoric acid derivative or any carboxylic acid derivative;
  • acidic oligomers are SR 9050 manufactured by Sartomer, Genorad 40 by Rahn, and maleic anhydride; and
  • organometallic adhesion promoter selected from an organo-silicon compound, an organo-titanium compound and an organo-zirconium compound such as Z-6030 manufactured by Dow Corning and NZ-37 and NZ-44 manufactured by Kenrich Petrochemicals.
  • the encapsulant formulation comprises between about 0.1 and 10% of at least one adhesion promoter of type (1) above and/or between about 0.01 and 5% of at least one adhesion promoter of type (2).
  • the addition of at least one addition promoter of type (2) to the encapsulant formulation, particularly where said at least one addition promoter is at least one organo-silicone, provides further crosslinking enabled by moisture curing over long periods of time.
  • the encapsulant formulation of the invention comprises between 5 and 50% of at least one acrylic polymer or oligomer, between 5 and 50% of at least one acrylic monomer and between 0 and 25% of at least one plasticizer.
  • the at least one plasticizer is an aliphatic plasticizer, such as esters of adipic acid, Eastman 168 Xtreme Plasticizer manufactured by Eastman and VELSICOL DOA manufactured by Velsicol.
  • One exemplary formulation according to the present invention comprises:
  • At least one aliphatic plasticizer in an amount ranging from 0 to 70% of the total weight of the formulation
  • At least one polymer selected from (1) poly(acrylic or methacrylic acid ester or amide or urethane) including copolymers and terpolymers thereof; (2) PVB including copolymers and terpolymers thereof; (3) cyclic olefin; (4) aliphatic polyester; (5) aliphatic polyether and (6) aliphatic polyurethane in an amount ranging from 0 to 70% of the total weight of the formulation;
  • HALS hindered amine light stabilizer
  • At least one organo-metallic adhesion promoter selected from silane, siloxanes, silazenes, titanates, zirconates and aluminates in an amount ranging from 0 to 10% of the total weight of the formulation;
  • At least one acidic monomer and/or oligomer and/or polymer in an amount ranging from 0 to 50% of the total weight of the formulation
  • At least one additive selected from UV-absorber, antioxidant, dye, pigment, tackifier, curing synergist, organic peroxide
  • the at least one acrylic monomer is selected from are lauryl methacrylate, butyl acrylate, octyl acrylate, decyl acrylate, iso-decyl acrylate, tridecyl acrylate, ethyl hexyl acrylate, ethoxylated ethyl hexyl acrylate, octyl decyl acrylate, di ethylene glycol 2-ethylhexyl ether acrylate, tetra decyl acrylate, cetyl acrylate, stearyl acrylate, behenyl acrylate, polyethylene glycol mono acrylate and caprolactone acrylate 2-ethyl hexyl acrylate, polyethylene glycol acrylate and any methacrylate equivalent thereof.
  • the oligomers and polymers are selected amongst those having any one or more of the above monomers.
  • the at least one aliphatic plasticizer is selected from adipic acid mono and di-ester, azelaic acid mono and di-ester, glutaric acid mono and di-ester, maleic acid mono and di-ester, and sebacic acid mono and di-ester.
  • the at least one polymer is selected from poly alkyl methacrylate or acrylate such as ELVACITE manufactured by Lucite, PVB such as S- LEC B by Sekisui and BUTVAR by Solutia, cyclic olefin such as TOPAS manufactured by Topas advanced polymers, poly methyl methacrylate (PMMA), polyurethane acrylates such as GENOMER 4256 manufactured by Rahn, amino resins such as CYMEL manufactured by Cytec, and hydrogenated butadiene rubber such as LIR-200 manufactured by Kuraray.
  • poly alkyl methacrylate or acrylate such as ELVACITE manufactured by Lucite
  • PVB such as S- LEC B by Sekisui and BUTVAR by Solutia
  • cyclic olefin such as TOPAS manufactured by Topas advanced polymers
  • PMMA poly methyl methacrylate
  • polyurethane acrylates such as GENOMER 4256 manufactured by Rahn
  • amino resins such as
  • the at least one HALS is, for example, TINUVIN 123 and 292 manufactured by CIBA.
  • Example for the at least one organo-metallic adhesion promoter are 3- (trimethoxysilyl)propyl methacrylate such as Z-6030 silane manufactured by Dow Corning, vinyltriethoxysilane, tetrapropyl orthosilicate, titanium(IV) butoxide such as that sold as TYZOR TBT by Du Pont, zirconium acrylate, organo-titanates and organo zirconates such as those sold by Kenrich petrochemicals as Ken-React additives, coordinate zirconates, neoalkoxy zirconates, zirconium propionate, Zircoaluminates, and Zirconium acetylacetonate.
  • 3- (trimethoxysilyl)propyl methacrylate such as Z-6030 silane manufactured by Dow Corning
  • vinyltriethoxysilane vinyltriethoxysilane
  • tetrapropyl orthosilicate titanium(IV) butoxide
  • the encapsulant formulation of the invention comprises also at least one photoinitiator which initiates polymerization and cross-linking of the unsaturated monomer or oligomer and said at least one adhesion promoting monomer or oligomer to form a dimensionally stable, soft and elastic encapsulant mass.
  • Non-limiting examples of said at least one photoinitiator are 2-hydroxy-2- methyl- 1 -phenyl-propan- 1 -one, 2,4,6-trimethylbenzoyl-diphenyl-phosphineoxide, 1 - hydroxy-cyclohexyl-phenyl-ketone, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentyl phosphine oxide, 1 - [4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl- 1 -propane- 1 - one, 2,2-dimethoxy-l,2-diphenylethan-l-one and 2-methyl-l[4-(methylthio)phenyl]-2- morpholinopropan- 1 -one.
  • said at least one photoinitiator is selected to be activated by light in the visible spectrum, so that curing may be achieved when light is provided through glass or other UV screening protective layers.
  • photoinitiators are phenylphosphineoxides such as Irgacure 819 manufactured by Ciba, and Lucirin TPO manufactured by BASF.
  • the acidic monomers may be selected from acrylic and methacrylic acid, maleic anhydride, SR 9050 by Sartomer and Genomer 7154 manufactured by Rahn.
  • the encapsulant formulation is a liquid at room temperature.
  • the formulation may be prepared by first forming two separate bulk formulations, in the form of an adhesive Part A and Part B, which may be combined to form the encapsulant formulation at a desired point in time, prior to application.
  • the encapsulant may be prepared by mixing the ingredients into one formulation to thereby obtain a ready-for-use encapsulate.
  • an adhesive Part A formulation may be prepared by first dissolving the solid or viscous liquid polymers in the monomers and/or oligomers used to provide a "syrup", which is herein referred to as Part A.
  • the solid or liquid additives such as the at least one photo initiator, at least one stabilizer, at least one UV absorber, peroxides, azo, catalysts, etc., are added into the plasticizer to obtain an additive liquid concentrate, herein referred to as Part B.
  • the two parts may be stored separately and mixed to form a clear solution prior to application.
  • the encapsulant formulation thus prepared may be applied by any means known in the art.
  • the encapsulant formulation is dispensed onto the open PV module before assembly, without applying any pressure or force, or by applying a low pressure derived from the weight of the assembled components.
  • the formulation is applied by pumping the encapsulant onto a substrate or into a pre-made cavity to be filled.
  • the pressure required to pump the liquid into the cavity is usually in the range of zero (free pouring) to about 1 atmosphere gauge. In some embodiments, the pressure is 0.5 atmosphere gauge. In other embodiments the pressure is between 0.1 and 0.4 atmosphere gauge. Examples to useful pumping methods are pneumatic dispensing, extrusion and syringe dispensing.
  • the formulation is applied by pouring.
  • curing of said formulation is enabled by means of UV and/or visible light, heat, IR irradiation or combinations thereof.
  • Such curing provides an encapsulant layer thickness ranging from 10 microns to 5 millimeters.
  • the formulations of the invention are cured to at least 90% conversion within 1 to 1 ,000 seconds.
  • curing of the uncured liquid encapsulant is achieved by employing a UV and/or visible light generated by a source selected from a mercury lamp, a plasma ignited lamp, a fluorescent bulb, a light emitting diode (LED), a halogen lamp and natural sun light.
  • a source selected from a mercury lamp, a plasma ignited lamp, a fluorescent bulb, a light emitting diode (LED), a halogen lamp and natural sun light.
  • the curing process comprises a curing step employing an artificial light (e.g., so as to provide conversion sufficient for handling), optionally followed by a further curing step initiated by natural sun light.
  • the encapsulant formulations and processes disclosed herein enable high speed and economical manufacturing of PV modules, without the need for lamination under high pressure and heat (as is the case with existing technology which employs EVA and PVB), long curing periods and expensive surface treatments (as is the case for example with addition curing silicone elastomers).
  • the encapsulant (at the uncured liquid state) according the present invention may additionally be cured onto a plastic or elastic mass by means of any one or more of free radical mechanism, cationic mechanism, anionic mechanism, condensation reaction, addition reaction, Michael addition reaction, and ring opening mechanism.
  • the curing may take place at both low temperatures (ambient or lower) or elevated temperatures.
  • the encapsulant of the present invention has excellent adhesion to thermoplastic and thermosetting materials such as PMMA, COC and PC without needing surface pretreatment, primer or any other adhesion promoting steps.
  • the presence of the low molecular weight monomers and plasticizers, especially unsaturated aliphatic esters such as acrylic and methacrylic acid esters enables mild swelling of the substrate by the encapsulant, so as an "alloy" interphase is formed thereby adhesion is achieved.
  • the swelling and miscible interface layer formation is achieved without stress-cracking of said transparent (amorphous) polymeric surfaces.
  • the cured layer of the encapsulant according to the present invention has adhesion peel strength to PMMA of greater than 1 pound per linear inch (PLI).
  • the cured layer of the encapsulant according to the present invention has adhesion peel strength to PMMA of greater than 3 pound per linear inch (PLI).
  • the cured layer of the encapsulant according to the present invention has adhesion tensile strength to PMMA of greater than 0.001 kilograms per square cm.
  • the cured layer has a refractive index of between 1.4 and 1.6.
  • Another method which was employed to demonstrate the improved adhesion (and the ability to withstand the stresses generated due to the thermal mismatch between the PV cell and the polymeric surface, e.g., glass and the (amorphous) transparent substrate) of the encapsulant of the invention to PMMA and glass is by bonding two plates, 100 mm x 100 mm in size and 3 -mm thick, one made of glass and the other of PMMA.
  • the bonding is achieved by applying 200-600-micron thick layer of said encapsulant between the plates, and curing by exposing to UV/visible light emitted from a medium pressure mercury lamp.
  • the bonded plates were subjected to thermal cycles ranging from -40°C to +85°C.
  • a laminate bonded with commercially available EVA film failed after two cycles.
  • a laminate bonded with commercially available addition type silicone elastomer (PV 6010 manufactured by Dow Corning) failed after three cycles.
  • a laminate comprising an adhesive layer according the present invention passed 100 cycles and even 250 cycles without any delamination.
  • the encapsulant according to the present invention requires minimal pressure or no pressure at all and usually flows and wets well at ambient, without needing external heat.
  • the manufacturing process employing the encapsulant of the invention is fast and economical.
  • heating is not required for lamination enables the manufacturing of CPV from relatively low heat deflection temperature materials, such as PMMA.
  • the cured encapsulant of the invention has a tensile storage modulus which varies from 100 MPa to 0.0001 MPa (a soft gel), when measured by Dynamic Mechanical Analysis (DMA) at 23 0 C, at IHz. In some embodiments, the modulus range is from about 20 MPa (tensile storage modulus) to 0.0001 MPa, when measured by Dynamic Mechanical Analysis (DMA) at 23°C. In order to minimize stresses at low temperature, the encapsulant is characterized by low modulus of elasticity at -4O 0 C.
  • the cured encapsulant of the invention has a modulus which varies from 100 MPa to 0.01 MPa, when measured by Dynamic Mechanical Analysis (DMA) at -40 0 C.
  • the low modulus minimizes stresses between the inorganic protective layer (glass for example) and the bonded plastic layers.
  • the stresses are generated due to thermal mismatch (difference in coefficient of thermal expansion), shrinkage during curing and due to difference in humidity uptake. This property is of high importance as the module is exposed to thermal cycles in the range of +85°C to -40 0 C.
  • Current thermoplastic adhesives such as EVA and PVB
  • Silicone adhesives are suitable for this purpose, but have poor adhesion to such (amorphous) transparent plastic materials, they tend to be inhibited easily and require long curing times at temperatures of 80 0 C or higher.
  • the cured encapsulant of the present invention has a modulus of less than 50 MPa and shore A hardness of lower than 85A, lower than 54A or lower than 2OA.
  • the cured encapsulant mass has a modulus of lower than 100 Megapascals (MPa). In other embodiments, the cured mass has a modulus of lower than 50 Megapascals (MPa). In still other embodiments, the cured mass has a modulus of lower than 20 Megapascals (MPa) at 23 0 C.
  • the cured encapsulant has a light transmission through 500 micrometers (microns) of cured mass of at least 85% of original light intensity in the wavelength range of 300 to 800 nanometers.
  • a formulation comprising at least one acrylic, aliphatic polyester or polyurethane polymer or oligomer, and at least one acrylic monomer or oligomer, at least one photo initiator and optionally at least one plasticizer and cured by exposing to UV and/or visible light, maintains its optical clarity for periods as long as 10,000 hours in accelerated UV weathering, despite its low modulus of elasticity and low cross-linking density.
  • the encapsulant in some of its embodiments, has a glass transition temperature (Tg) of lower than 30°C; in other embodiments, lower than 10°C, still other embodiments, lower than -10°C, lower than -20°C, lower than -30°C, or lower than -40 0 C.
  • Tg glass transition temperature
  • the glass transition is measured by Thermal Mechanical Analysis (TMA), dynamical mechanical analysis (DMA) or by Differential Scanning calorimetry (DSC).
  • Tg can be adjusted by selection of the monomers, wherein high content of long chain alkyl acrylates or polyether acrylates, affect the Tg.
  • the Tg of a homopolymer of isodecyl acrylate is -60 0 C and the Tg of a homopolymer of 2(2-ethoxyethoxy) ethyl acrylate (EOEOEA) is -54°C.
  • a high content of such monomers enables a Tg which is lower than -10 0 C and even lower than -20 0 C.
  • the homopolymer of tetrahydro furfuryl acrylate (THFA) has Tg of -28°C, and since THFA has excellent adhesion to PMMA, an amount of 5-50% endows the encapsulant with both lower Tg and excellent adhesion.
  • the formulation comprises a combination of THFA and EOEOEA. These monomers or similar, may be part of the acrylic polymer or oligomer, as well as portion or all of the unsaturated monomer.
  • plasticizer typically selected amongst linear, branched and/or ethoxylated aliphatic mono or di-acid plasticizers.
  • the encapsulant according to the present invention additionally has similar or even better resistance to oxidation and photo-degradation than EVA and PVB, a resistance that is evident from the lower tendency to yellow and to crack over time.
  • This improved resistance is provided by the elimination of vinyl acetate groups that are typical to EVA and PVB, since the acetate group is disassociated from the main chain during exposure to heat and/or UV light.
  • the by-product of this un-desired reaction is acetic acid that causes corrosion of the PV cell conductors.
  • the encapsulant formulation comprises no acetate groups, and thus is much more resistant against thermal and photo induced degradation.
  • Another advantage of the encapsulant according the present invention is the minimal thermal history during processing, since neither extrusion, nor high temperature lamination is required. This lowered thermal history provides polymer mass that has lower unsaturated groups, lower gel content and lower weakened points.
  • a PV module comprising at least one bonding layer of a cured formulation according to the invention.
  • the PV module comprises at least one PV cell and at least one surface selected from PMMA, COC and PC, wherein bonding between said cell and said at least one surface is provided by a bonding layer comprising the encapsulant formulation according to the present invention.
  • a PV module consists of several interconnected cells or thin films (being capable of providing electrical voltage and/or current in response to light) that are embedded or bonded to one or two, e.g., (amorphous), transparent plastic (e.g., PMMA, COC or PC) surfaces (e.g., prisms, lenses, reflectors), with a bonding layer (encapsulant) of a formulation according to the invention.
  • the bonding layer is the cured film or mass derived from a formulation of the present invention.
  • the PV module has a transparent front (top) side (being glass or a polymeric material), at least one optical element (a prism, a lens, a frensel lens, a non- flat optical concentrator, etc) layer made of, e.g., an amorphous transparent plastic material and an encapsulated PV cell.
  • the backside may or may not be transparent.
  • the PV module may comprise any number of PV cells. In some embodiments, the PV module comprises more than 1 cell. In other embodiments, the PV module comprises at least 2 cells.
  • the individual PV cells in the module may be any device, semiconductor (of any semiconductor material, being in the form of a single crystal, poly-crystalline or amorphous) or organic or inorganic that provides electrical potential and/or current when irradiated by light, particularly in the range of wavelengths of 200 to 1,200 nanometers.
  • the PV cells are typically interconnected with thin contacts on the upper and bottom side of the, e.g., semiconductor material.
  • the assembly may be any optical assembly having at least one polymeric surface to be bonded as detailed herein.
  • the cured encapsulant mass is derived from the liquid formulation of the invention, as defined.
  • the assembly may be the PV module, as defined.
  • the PV module is a concentrating photovoltaic module (CPV) having three or more layers including the PV cell, a bonding layer and a concentrating object.
  • said CPV is of the structure shown in Fig. 1.
  • layer (1) is a concentrating object (CO) that collects light (e.g., sunlight) and concentrates it on the photovoltaic cell (5).
  • CO concentrating object
  • the light intensity on interface between layers (4) and (5) is higher than the light intensity on interface of the outer, air-exposed layer (3) and the surrounding air.
  • the CO comprises of polymeric material having transparency in the UV-visible spectrum, high durability against thermal and photo-degradation and ease of manufacturing and is selected in a non-limiting fashion from poly methyl methacrylate (PMMA), polycarbonate (PC) and cyclic olefin (COC).
  • PMMA poly methyl methacrylate
  • PC polycarbonate
  • COC cyclic olefin
  • the above CPV multilayer structure according to the present invention has an outer inorganic transparent layer (3) having thickness between 0.1 to 10 millimeters, said outer inorganic layer being selected from glass, quartz, alumina, fused silica and sol-gel coated polymeric sheet.
  • the protective layer is glass.
  • the photovoltaic cell constituting layer 5 may be any device, semiconductor or organic or inorganic that provides electrical potential and/or current when irradiated by light, especially in the range of wavelengths of 200 to 1200 nanometers.
  • Layers (2) and (4) of the CPV of Fig. 1 are each a bonding layer comprising an encapsulant formulation according to the invention.
  • Such a multilayered CPV may be manufactured by applying, as disclosed above, the formulation of the invention onto at least one face of layers 1 and 3 and at least one face of layers 1 and 5, and assembling the layers one on top of the other such that a multilayer is achieved.
  • Layers 2 and 4 are then cured by means of radiation including one or more of UV, visible light, IR, and/or heating.
  • Fig. 1 is an exemplary CPV according to the present invention.
  • Fig. 2 is an exemplary CPV according to the present invention.
  • PV modules prepared according to the present invention included an outer layer made of low iron ultra-clear solar glass (such as Saint-Gobain SECURIT ALBARINO S 3.2-4mm thick with light transmission level of 91.5%).
  • the concentrating object employed was in the form of a layer of PMMA resin PLEXIGLAS 8N manufactured by Evonik, and the photovoltaic cell was a silicone cell, 200 ⁇ m thick.
  • Table 1 different encapsulant formulation according to the present invention: EOEOEA- 2-(2-ethoxyethoxy) ethyl acrylate; Ur-Acryl (aliphatic urethane acrylate)- CN 9001, manufactured by Sartomer; polyacrylate solution- Doublemer 353, manufactured by Double Bond Chemical from Taiwan; Plasticizer- bis[2-(2-butoxyethoxy)ethyl] adipate; HALS- Tinuvin 292 manufactured by CIBA; photo initiator- Irgacure 819, manufactured by CIBA; silane- 3-(methacryloyloxy) propyl]trimethoxysilane, sold as Dow Corning ® product Z-6030; and peroxide- benzoyl peroxide.
  • Formulas 1, 2, 3 and 5 according to the present invention were cured by medium pressure mercury lamp providing 75-100 mW/cm 2 in the range of 320-390 ran for period of 30 seconds.
  • Formula 4 according to the invention was cured 30 minutes at 100°C.
  • Adhesion (encapsulation) quality was evaluated by exposure to 500 thermal cycles at a temperature between -40 to +85°C. All 4 formulations were found to provide the required encapsulation.
  • Samples of CPV according to the present invention were exposed to QUV accelerated ageing (light penetrated from glass side), following the protocol:
  • Formulas 2, 3 and 4 - showed no discoloration and no cracking of the bonding adhesive layers and PMMA object.
  • Formula 1 showed a slight yellowing.
  • Comparative example 1 UV curable acrylate based formulas that comprised aromatic monomers, oligomers and plasticizers, provided good adhesion to PMMA and glass/cell, but turned dark brown after exposure to UV light in the QUV accelerated test.
  • Comparative example 2 Two-component aliphatic polyurethane (aliphatic polyester polyol, cured by aliphatic tri-isocyanate, and plasticized by aliphatic plasticizer) provided sufficient UV resistance, but had poor adhesion to PMMA and medium-poor adhesion to the glass and cell.
  • Comparative example 3 A reference PV module wherein adhesive layers were PV 6010 addition type silicone gel encapsulants, manufactured by Dow corning, failed after less than 5 cycles due to poor adhesion between the silicone encapsulants and the PMMA layer. The adhesion was so poor, that in some samples, delamination and blisters were observed immediately after curing, prior to any ageing test.
  • Fig. 2 illustrates the structure of an exemplary CPV panel according to the present invention. This non-limiting CPV solar panel was assembled from the following layers -
  • the mixture has a viscosity at ambient lower than 5,000 centipoises and it is applied between the glass and PMMA and between the PV cell and PMMA.
  • the liquid encapsulant/adhesive propagates spontaneously at ambient with no need to apply heat/ pressure, until gaps are filled.
  • the layer is then cured (cross-linked) by exposing to medium pressure mercury UV source, for 30 seconds, so as the cured bonding layer is non-tacky (or in some cases tacky), resilient, soft, transparent, void-free, haze-free and bonded very good to glass, PMMA and PV cell.
  • Prism concentrators made of PMMA and mirror foils (30).
  • the PMMA is injection molded and the metal mirrors are bonded to the PMMA prism by same bonding layer used for glass-PMMA and PV cell-PMMA bonding;
  • a back sheet (60) made of anodized aluminum for sealing from humidity and oxidation, and for heat dissipation.
  • Light rays entering the panel are trapped in the prism (via total internal reflection) and directed toward the PV cell.

Landscapes

  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Macromonomer-Based Addition Polymer (AREA)
  • Photovoltaic Devices (AREA)
  • Structures Or Materials For Encapsulating Or Coating Semiconductor Devices Or Solid State Devices (AREA)

Abstract

L'invention concerne une formulation encapsulant un liquide photo-/thermodurcissable destinée à être utilisée dans la construction d'une variété d'assemblages optiques.
EP09765166A 2008-11-12 2009-11-12 Module photovoltaïque concentrateur Withdrawn EP2351104A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US19325908P 2008-11-12 2008-11-12
PCT/IL2009/001063 WO2010055507A2 (fr) 2008-11-12 2009-11-12 Module photovoltaïque concentrateur

Publications (1)

Publication Number Publication Date
EP2351104A2 true EP2351104A2 (fr) 2011-08-03

Family

ID=42170482

Family Applications (1)

Application Number Title Priority Date Filing Date
EP09765166A Withdrawn EP2351104A2 (fr) 2008-11-12 2009-11-12 Module photovoltaïque concentrateur

Country Status (3)

Country Link
US (1) US20110214738A1 (fr)
EP (1) EP2351104A2 (fr)
WO (1) WO2010055507A2 (fr)

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011048595A2 (fr) 2009-10-21 2011-04-28 Pythagoras Solar Inc. Fenêtre
ITAN20100087A1 (it) * 2010-06-01 2011-12-02 Benedetto Carlozzo Procedimento per la realizzazione di lastre trasparenti in polimetilmetacrilato con all'interno film fotovoltaici per la produzione di energia solare.
US20130280544A1 (en) 2010-12-28 2013-10-24 Akzo Nobel Coatings International B.V. Radiation curable coating compositions for metal
BR112013019019A2 (pt) * 2011-01-28 2016-10-04 Evonik Roehm Gmbh dispositivo de concentração solar
US8680171B2 (en) 2011-07-01 2014-03-25 Arkema France Method of encapsulating a photovoltaic cell and encapsulated photovoltaic cell
US9202958B2 (en) 2011-11-03 2015-12-01 Guardian Industries Corp. Photovoltaic systems and associated components that are used on buildings and/or associated methods
JP2013133440A (ja) * 2011-12-27 2013-07-08 Nitto Denko Corp 粘着剤、粘着剤層、および粘着シート
KR101549726B1 (ko) * 2012-12-20 2015-09-02 제일모직주식회사 봉지용 조성물, 이를 포함하는 장벽층 및 이를 포함하는 봉지화된 장치
US8796061B2 (en) * 2012-12-21 2014-08-05 Sunpower Corporation Module assembly for thin solar cells
TWI640564B (zh) * 2013-02-21 2018-11-11 三菱化學股份有限公司 Resin composition and sealing material for crosslinking
US9960303B2 (en) 2013-03-15 2018-05-01 Morgan Solar Inc. Sunlight concentrating and harvesting device
US9714756B2 (en) 2013-03-15 2017-07-25 Morgan Solar Inc. Illumination device
US9595627B2 (en) 2013-03-15 2017-03-14 John Paul Morgan Photovoltaic panel
WO2014138857A1 (fr) 2013-03-15 2014-09-18 John Paul Morgan Panneau d'éclairage, ensemble optique à interface améliorée et panneau d'éclairage aux tolérances de fabrication améliorées
JP6351459B2 (ja) * 2014-09-22 2018-07-04 株式会社東芝 太陽電池モジュール
JP6501906B2 (ja) * 2015-11-25 2019-04-17 三井化学東セロ株式会社 太陽電池モジュール
JP2019513307A (ja) 2016-03-30 2019-05-23 エクソンモービル・ケミカル・パテンツ・インク 太陽電池用途向けの熱可塑性加硫物組成物
EP3437143B1 (fr) * 2016-03-30 2023-04-05 ExxonMobil Chemical Patents Inc. Compositions de vulcanisat thermoplastique pour des applications de cellules photovoltaïques
JP2021039984A (ja) * 2019-08-30 2021-03-11 パナソニック株式会社 太陽電池モジュール、太陽電池モジュール作製方法
CN113999345B (zh) * 2021-11-30 2023-08-29 江苏铁锚玻璃股份有限公司 球型有机玻璃的配方及其制备方法
CN114566559A (zh) * 2022-03-31 2022-05-31 杭州福斯特应用材料股份有限公司 一种光伏组件

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6075065A (en) * 1996-12-20 2000-06-13 Takeda Chemical Industries, Ltd. Photocurable resin composition and a method for producing the same
JP4163653B2 (ja) * 2004-02-27 2008-10-08 株式会社日本触媒 光学部品用硬化性組成物
CA2613987A1 (fr) * 2005-07-07 2007-01-18 Nippon Kayaku Kabushiki Kaisha Agent d'etancheite pour convertisseur photoelectrique et convertisseur photoelectrique utilisant ledit agent
US20080053516A1 (en) * 2006-08-30 2008-03-06 Richard Allen Hayes Solar cell modules comprising poly(allyl amine) and poly (vinyl amine)-primed polyester films
US20080128018A1 (en) * 2006-12-04 2008-06-05 Richard Allen Hayes Solar cells which include the use of certain poly(vinyl butyral)/film bilayer encapsulant layers with a low blocking tendency and a simplified process to produce thereof
US8080726B2 (en) * 2007-04-30 2011-12-20 E. I. Du Pont De Nemours And Company Solar cell modules comprising compositionally distinct encapsulant layers

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2010055507A2 *

Also Published As

Publication number Publication date
WO2010055507A3 (fr) 2011-01-13
US20110214738A1 (en) 2011-09-08
WO2010055507A2 (fr) 2010-05-20

Similar Documents

Publication Publication Date Title
US20110214738A1 (en) Concentrating photovoltaic module
US20110214717A1 (en) Light curable photovoltaic cell encapsulant
CN108026429B (zh) 可固化和光学透明的压敏粘合剂及其用途
JP4034382B2 (ja) 太陽電池モジュール用保護シート
JP5594959B2 (ja) 太陽電池素子封止材
EP2566902B1 (fr) Matière d'encapsulation durcissable par uv
EP3070748A1 (fr) Feuille d'adhésif à base de silicone ayant des propriétés de blindage contre un rayonnement ultraviolet pour sceller de manière étanche une photopile et module de photopiles l'utilisant
WO2011065157A1 (fr) Film d'étanchéité pour cellules solaires, et cellules solaires
US9123836B2 (en) Solar cell sealing film and solar cell using the same
EP2892080A1 (fr) Paire de films de scellage pour cellule solaire et procédé de fabrication de module de cellule solaire l'utilisant
US20130000725A1 (en) Method of encapsulating a photovoltaic cell and encapsulated photovoltaic cell
EP2770541B1 (fr) Film de scellage pour cellules solaires, et cellule solaire l'utilisant
JP2011032451A (ja) 複合粘着テープ及びそれを用いた太陽電池モジュール
JP5857460B2 (ja) 太陽電池モジュール用封止材組成物
JP5482276B2 (ja) 太陽電池用封止材及び太陽電池モジュール
JP2011119475A (ja) 太陽電池モジュールの製造方法
KR101106240B1 (ko) 태양전지용 봉지재 및 이를 포함하는 태양전지 모듈
KR101414239B1 (ko) 백색 ｅｖａ 수지층을 포함하는 태양전지 모듈
JP2011152686A (ja) エチレン−酢酸ビニル共重合体シート、その製造方法、並びにそれを用いた合わせガラス及び太陽電池
KR20170090229A (ko) 경화성 점착제 조성물, 상기 조성물을 포함하는 봉지재층을 포함하는 태양전지 모듈 및 그 제조방법
EP3753910A1 (fr) Composition de résine pour film de couche intermédiaire de verre feuilleté ou matériau d'encapsulation de cellule solaire, film de couche intermédiaire de verre feuilleté, verre feuilleté, matériau d'encapsulation de cellule solaire, et module de cellule solaire
JP5806373B2 (ja) 太陽電池用封止膜及びこれを用いた太陽電池
DOE MASTER
JP2011238862A (ja) 太陽電池用封止膜及びこれを用いた太陽電池
JP2015185802A (ja) 太陽電池モジュール用裏面保護シート、太陽電池モジュールおよびその製造方法

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20110517

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR

DAX Request for extension of the european patent (deleted)
17Q First examination report despatched

Effective date: 20140116

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20140527